Jong Hyun Ahn

Bio: Jong Hyun Ahn is an academic researcher from Yonsei University. The author has contributed to research in topics: Graphene & Graphene nanoribbons. The author has an hindex of 74, co-authored 287 publications receiving 39786 citations. Previous affiliations of Jong Hyun Ahn include National University of Singapore & University of Illinois at Urbana–Champaign.

Biodegradable and bioabsorbable sensors based on two-dimensional materials

Abstract: Two-dimensional (2D) materials, including graphene and transition metal dichalcogenides (TMDCs), have attracted considerable attention for the last decade due to their unique electrical, optical and mechanical properties. Recently, as their unique characteristics of biocompatibility and biodegradation are known, research on applying them in diagnostic and therapeutic applications has received considerable attention. This review provides a broad overview of recent reports on the biocompatibility and biodegradability of 2D materials and highlights recent progress in biodegradable and bioabsorbable sensors for diagnostic and therapeutic applications.

Conductance modulation in topological insulator Bi2Se3 thin films with ionic liquid gating

Abstract: A Bi2Se3 topological insulator field effect transistor is investigated by using ionic liquid as an electric double layer gating material, leading to a conductance modulation of 365% at room temperature. We discuss the role of charged impurities on the transport properties. The conductance modulation with gate bias is due to a change in the carrier concentration, whereas the temperature dependent conductance change is originated from a change in mobility. Large conductance modulation at room temperature along with the transparent optical properties makes topological insulators as an interesting (opto)electronic material.

Conductance modulation in topological insulator Bi2Se3 thin films with ionic liquid gating

Abstract: A Bi2Se3 topological insulator field effect transistor is investigated by using ionic liquid as an electric double layer gating material, leading to a conductance modulation of 365% at room temperature We discuss the role of charged impurities on the transport properties The conductance modulation with gate bias is due to a change in the carrier concentration, whereas the temperature dependent conductance change is originated from a change in mobility Large conductance modulation at room temperature along with the transparent optical properties makes topological insulators as an interesting (opto)electronic material

Mechanical flexibility of zinc oxide thin-film transistors prepared by transfer printing method

Abstract: In the present study, we demonstrate the performance of Zinc oxide thin film transistors (ZnO TFTs) array subjected to the strain under high bending test and the reliability of TFTs was confirmed for the bending fatigue test of 2000 cycles. Initially, ZnO TFTs were fabricated on Si substrate and subsequently transferred on flexible PET substrate using transfer printing process. It was observed that when the bending radius reached ≥ 11 mm then cracks start to initiate first at SiO2 bridges, acting as interconnecting layers among individual TFT. Whatever the strain is applied to the devices, it is almost equivalently adopted by the SiO2 bridges, as they are relatively weak compared to rest of the part. The initial cracking of destructed SiO2 bridge leads to the secondary cracks to the ITO electrodes upon further increment of bending radius. Numerical simulation suggested that the strain of SiO2 layer reached to fracture level of 0.55% which was concentrated at the edge of SiO2 bridge layer. It also suggests that the round shape of SiO2 bridge can be more fruitful to compensate the stress concentration and to prevent failure of device.

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.